ok as you probably know my friend has a 2004 gmc sierra with the 4.3l v6 now it has hit 100+ degrees out side and you have to use the air conditioning alot now. we havee to use the air conditioning for an extended time, his truck will stall he took it to a mechanic and They said that it is because of dust and stuff since we live in a desert. im thinking it is just an air filter, but the mechanic should have know that. so now im looking for your opinions. idk what the stuff is though??